Table 1: Evidence for cross-reactivity of influenza virus-specific CTL.

SubtypeComments Ref.
Priming subtypeCross-reaction withSpecies

H2N1H3N2MouseCross-reactivity confirmed in Cr-release assays using cultured splenocytes of primed mice[28]
H1N1H2N2
H3N2
MouseCross-reactivity confirmed in Cr-release assays using splenocytes of primed mice[24]
H3N2H1N1MouseTarget cells expressing NP from H1N1 recognized by cultured splenocytes from primed mice[29]
H3N2H1N1MouseCross-reactive cultured splenocytes recognize inner proteins of influenza A virus[30]

H3N2H1N1HumanCross-reactive CTLs recognize NP, M1, or PB2[31]
Seasonal influenzaH5N1HumanCross-reactive CTLs were detected in the blood of healthy human subjects not exposed to H5N1 virus[3234]
pH1N1H1N1HumanT cells specific for the NP418 epitope induced by the 2009 pH1N1 cross-react with the 1918-H1N1 variant but not with contemporary variants[35]
Seasonal influenza2009 pH1N1HumanCross-reactive CTLs were detected in the blood of healthy human subjects not exposed to 2009 pH1N1 virus[36]